1. Field of the Invention
The present invention relates to radio direction finders generally, and particularly to those having a plurality of antenna elements; the angle of arrival of an electromagnetic wave being determined from the phases occurring at the elements.
2. Description of the Prior Art
A direction finder of the kind to which the invention applies is described in an article by F. Steiner, entitled "Grossbasispeiler nach dem Dopplerprinzip" and published in Germany in the periodical "Nachrichtentechnische Fachberichte" 12 (1958).
Wide-base direction finders are relatively insensitive to errors caused by multipath propagation, however, they have the disadvantage of occupying much space. Circular and linear antenna arrays are known which are 5 .lambda. in diameter and length, respectively. However, the smaller the base, the more the measurement result will be affected by errors due to multipath propagation.
The manner in which the present invention deals with this problem will be evident as the description proceeds.